Recently, a stub (also referred to as a glass rod) or the like has been used in optical communication devices. The stub or the like is placed on an optical axis of a light source exiting from an optical fiber for the purpose of imparting functions such as coupling, branching, and splitting of light and also is mounted on optical communication devices such as an optical receptacle.
For example, Patent Document 1 mentioned below discloses an optical receptacle in which a stub is inserted into a base end part of an inner hole formed in the main body of a semiconductor module, and an end face of the stub is brought into contact with an end face of a plug ferrule inserted into an end side of the above inner hole. The end face (B side in the Document), to be brought into contact with the end face of the ferrule, in the above stub is subjected to spherical grinding. Furthermore, recently, there has been investigated an optical receptacle in which the stub to be inserted into the inner hole of the ferrule is fixed to the inner surface of a sleeve directly by heat treatment. In such an optical receptacle, the sleeve and the stub are strongly fixed and the optical receptacle can realize reduction of production costs and decrease in connection loss and further the adhered position of the stub does not change even under exposure to temperature change and high-temperature and high-humidity environment, so that decrease in coupling efficiency can be inhibited as far as possible.    Patent Document 1: JP-A-4-223412